Envelope opener

Abstract

An envelope opener is formed of a rectangular casing having a central transverse guide slot, two cutting disks project into the slot from either side and have mutually interfacing edge portions thereat. A spring resiliently maintains the edge portions of the disks in constant contact in the slot. The guide slot has an upwardly convex bottom surface to reduce friction of an envelope being guided through the slot.

What we claim is: 
     
       1. An envelope opener comprising a rigid casing having a first recess and a second spaced-apart recess formed therein; each said recess being formed around a fixed axial pin; first and second collars, each being rotatably mounted on one of said axial pins; a first cutting disk, being embedded into an intermediate radially outward annular cavity in said first collar, and a second cutting disk, being embedded into an intermediate radially outward annular cavity in said second collar; a guide-slot extending transversely of said casing between and partially intersecting said recesses; each said cutting disk having a radially outward edge portion extending in said guide-slot in overlapping relationship with the other cutting disk edge portion thereby defining two transversely-spaced cutting nips; a compression spring, fitted around the axial pin of said first collar and intermediate said first collar and the bottom of said first recess; said first cutting disk radially outward edge portion being in a lower position relative to said radially outward edge portion of the second cutting disk in said slot; two covers to close said casing on both sides of said slot; said compression spring thereby upwardly biasing said first cutting disk against said second cutting disk; and a raised inner annular part being formed in the top surface of said second collar, so as to frictionally contact the inner surface of the corresponding said cover. 
     
     
       2. A cutting device for shearingly opening an edge portion of an envelope, comprising a pair of similar first and second casings, each having a top and a bottom wall and at least two opposite side walls, a strip plate interconnecting said bottom walls in coplanar fashion to define a horiz ontal channel between said casings; first and second shafts, integral to and upwardly projecting from the bottom wall of said first and second casings, respectively, to the corresponding casing top walls, and around which are rotatively freely mounted first and second hub members, respectively; first and second cutting disks, embedded in the radially outer peripheral edge of said first and second hub members, respectively, and each having a radially outer edge portion engaging through an intermediate section of said channel; wherein said cutting disks edge portions overlap each other; and a spring member mounted around said first casing shaft below said first hub member, to upwardly bias said first hub member, so as to bias said first cutting disk edge portion upwardly against the underface of said second cutting disk edge portion, whereby said second hub member frictionally abuts against said second casing top wall but said first hub member remains spaced from said first casing top wall, said envelope edge portion engageable through either end of said channel to rotate said cutting disks during its displacement therealong. 
     
     
       3. A cutting device as in claim 2, wherein the top face of said strip plate is convex in longitudinal vertical section. 
     
     
       4. A cutting device as in claim 2, wherein the top walls of both casings are removable covers for facilitating maintenance of the cutting disks.